Exhibit 5.1

                     [Debevoise & Plimpton LLP Letterhead]


March 19, 2004

International Paper Company
400 Atlantic Street
Stamford, Connecticut 06921

Ladies and Gentlemen:

     This opinion is furnished to you in connection with the Registration
Statement on Form S-3 (File No. 333-103760) (the "Registration Statement") and
the Prospectus Supplement, dated March 15, 2004 (the "Prospectus Supplement"),
to the Prospectus, dated March 27, 2003, of International Paper Company, a New
York corporation (the "Company"), in connection with the issuance and sale by
the Company of $600,000,000 aggregate principal amount of its 4.00% Notes due
2010 (the "2010 Notes") and $400,000,000 aggregate principal amount of its 5.25%
Notes due 2016 (together with the 2010 Notes, the "Notes"). The Notes will be
issued pursuant to the Indenture, dated as of April 12, 1999 (the "Base
Indenture"), between the Company and The Bank of New York, as trustee (the
"Trustee"), as amended by the Supplemental Indenture, dated as of March 18, 2004
(the "Supplemental Indenture"; such Base Indenture, as supplemented and amended
by the Supplemental Indenture, being referred to herein as the "Indenture"),
between the Company and the Trustee.

     In so acting, we have examined originals or certified, conformed or
reproduction copies of such agreements, instruments, documents and records of
the Company, such certificates of public officials, and such other documents,
and have made such investigations of law, as we have deemed necessary or
appropriate for the purposes of this opinion. In all such examinations, we have
assumed without investigation the legal capacity of all natural persons
executing documents, the genuineness of all signatures on original or certified
copies, the authenticity of all original or certified copies and the conformity
to original or certified documents of all copies submitted to us as conformed or
reproduction copies.  We have relied as to factual matters upon, and have
assumed the accuracy of, the statements made in the certificates of officers of
the Company delivered to us and certificates and other statements or information
of or from public officials and officers and representatives of the Company and
others. In rendering the opinion expressed below, we have assumed that the
Trustee has the power and authority to enter into and perform its obligations
under the Indenture; the Indenture has been duly authorized, executed and
delivered by the Trustee and is valid, legally binding and enforceable against
the Trustee in accordance with its terms; and the Notes have been duly
authenticated by the Trustee in the manner provided in the Indenture.


International Paper Company                   2                   March 19, 2004

     Based on the foregoing, and subject to the further qualifications set forth
below, we are of the opinion that the Notes have been validly issued and
constitute valid and binding obligations of the Company.

     The opinion set forth above is subject to the effects of (i) bankruptcy,
insolvency, fraudulent conveyance, fraudulent transfer, reorganization and
moratorium laws, and other similar laws relating to or affecting enforcement of
creditors' rights or remedies generally, and (ii) general principles of equity
(whether such principles are considered in a proceeding at law or equity),
including, without limitation, concepts of good faith, reasonableness and fair
dealing and standards of materiality.

     The opinion set forth above is limited to the laws of the State of New
York, as currently in effect.

     We hereby consent to the filing of this opinion as an exhibit to the
Company's Form 8-K filed on March 19, 2004, incorporated by reference in the
Registration Statement, and to the reference to our firm under the caption
"Legal Matters" in the Prospectus Supplement. In giving such consent, we do not
thereby concede that we are within the category of persons whose consent is
required under Section 7 of the Securities Act or the rules and regulations of
the Commission thereunder.

                                           Very truly yours,



                                           /s/  Debevoise & Plimpton LLP